[PATCH -stable,5.4 9/9] netfilter: nf_tables: hold mutex on netns pre_exit path

[Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>]

[ 3923b1e4406680d57da7e873da77b1683035d83f ]

clean_net() runs in workqueue while walking over the lists, grab mutex.

Fixes: 767d1216bff8 ("netfilter: nftables: fix possible UAF over chains from packet path in netns")
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
 net/netfilter/nf_tables_api.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index a1b889e2748d..1976375c1369 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -7858,7 +7858,9 @@ static int __net_init nf_tables_init_net(struct net *net)
 
 static void __net_exit nf_tables_pre_exit_net(struct net *net)
 {
+	mutex_lock(&net->nft.commit_mutex);
 	__nft_release_hooks(net);
+	mutex_unlock(&net->nft.commit_mutex);
 }
 
 static void __net_exit nf_tables_exit_net(struct net *net)
-- 
2.30.2